The Hertfordshire Yeomanry was a Yeomanry Cavalry regiment of the British Army that could trace its formation to the late 18th century. First seeing mounted service in the Second Boer War and World War I, it subsequently converted to artillery. Three regiments saw service in World War II, one of which was captured at the fall of Singapore. It continued through various postwar amalgamations and its lineage was maintained by 201 (Hertfordshire and Bedfordshire Yeomanry) Battery, 100th (Yeomanry) Regiment Royal Artillery until that unit was placed in suspended animation in 2014.